ES2197433T3 - PACK OF OBJECTS PACKED WITH A PLASTIC FILM, PLASTIC FILM FOR THE PACKING OF A PACKAGE, AND PROCEDURE OF MANUFACTURE OF THE PLASTIC FILM. - Google Patents

Abstract

The package (1), comprising a series of objects (2) in one or more layers, is wrapped in plastics film (3) with a preferred tearing direction (D) and a zone (A) of reduced strength across it. The zone of reduced strength is made from rows of perforations (7, 9, 10) lying perpendicular to the preferred tear direction. This creates a zone with a mechanical strength which is sufficient to hold the packaged articles in position, while being sufficiently weak to allow the package to be opened at any point along the zone without the aid of a tool. The film is in the form of coextruded polyethylene/ionomer layer, and especially comprising at least one layer of a polyolefin and at least one layer of an ionic copolymer. The perforations are between 5 and 30 mm apart and cover a zone 30-100 mm wide.

Description

Package of objects packed with a film plastic, plastic film for packing a package, and Plastic film manufacturing procedure.

The invention refers to a package of objects, such as canned cans, drums, bottles, etc., packed with a plastic film that It has a preferred starting address, being several objects arranged side by side on one or several floors superimposed, the film being folded in one direction winding around the objects it encloses, being provided opening means in the film to facilitate its plucking

A package of this type is prepared from a known way by binding the group of objects. The tie it consists of surrounding the set of objects to be packaged with a heat shrinkable plastic film, in particular with a heat shrinkable polyethylene film. The cover made with the film is welded on the edges that are coated so that form a wrap around the grouped objects. The angry objects can be obtained, for example, by the heat effect caused by the narrowing of the film around the objects it encloses. The two open ends of the wrap shrink to form at the two ends of the package an oval shaped opening, usually called a lunula.

The opening of the package and the extraction of Objects pose a problem.

In fact it is desired to avoid the use of a cutting tool, which is not always available immediately when you want to extract one of the objects, and that also runs the risk of deteriorating objects and / or causing a tear poorly controlled film, releasing a number of objects higher than desired.

A solution following the preamble of the claims 1 and 12, already proposed by the document EP-A-0537079, consists of providing as a means of opening tabs, for example in shape rectangular, whose largest dimension is oriented parallel to the preferred starting direction, these tabs being previously trimmed following its two major sides and one side less. Such tabs are made by type marks `` die '', in some places distant from each other.

This solution, while constituting a progress, presents several drawbacks, especially the discontinuous realization of these brands, as well as the limitation of the choice of places to locate the openings that should correspond to these tabs.

The invention has the objective, above all, of provide a package of objects in which the opening means of the plastic film allow easy opening and controlled of the package constituted by the package of objects in a number of points as high as possible, so as to allow the user choose the most appropriate place to perform each opening.

According to the invention, the object package is characterized in that the opening means of the film of plastic matter comprise a continuous area of weakening oriented transversely to the preferred direction of tearing, and forming a belt surrounding the package, having this zone of weakening a mechanical resistance what strong enough to withstand tensile stresses exerted on the film to enclose the objects, but what low enough to allow film opening no tool anywhere in the area, by creating of an area where to grab a tongue and pull on the tongue following a direction transverse to the direction of the zone of weakening

Advantageously, the continuous zone of weakening is perpendicular to the preferred direction of plucking

Preferably, the continuous zone of weakening comprises at least one perforation line, in particular regularly spaced.

Advantageously, the continuous zone of weakening comprises a central perforation line surrounded by two parallel perforation lines, separated from the line central, and in which the distance between two perforations successive is greater than the distance between two perforations successive to the center line. Preferably, the distance between two successive perforations of the outer lines is equal to double the distance between two line perforations central.

The perforations of the two outer lines are advantageously aligned with a line perforation central following an orthogonal direction to the central line. The drawings created by the perforations are thus shaped like a I.

The plastic packaging film is preferably a double layer film whose direction of Preferred starting is perpendicular to the direction of extrusion. The film is in particular a polyethylene film ionomeric coextruded Such a movie can be consisting of at least one layer of polyolefin and at least a layer of an ionic copolymer.

The perforation lines can be distant from 5 to 30 mm, over a width of 30 to 100 mm.

The invention also refers to a plastic film for fastening package objects, presenting this film a preferred starting direction and being characterized by the presence of a continuous area of cross-oriented weakening, especially perpendicularly, to the preferred starting direction.

This continuous weakening zone comprises at least one line of regularly spaced perforations, and preferably at least three perforation lines, that is a central line in which the perforations are less separated that in two outer lines parallel to the center line and located on both sides, performing the perforations of the line central and outer lines preferably some drawings in l.

In the case of a plastic film whose preferred starting direction is perpendicular to the extrusion direction, a procedure for preparing the film consists of performing the perforations during the unwind or roll the film before packing, following its entire length, particularly during extrusion, the rewind, print or tying, using a device consisting of needle rollers with a reverse part in the form of cylindrical brush The plastic film for drilling it slides between the needle roller and its reverse side.

This operation can be repeated over the width of the film, in consideration of the end use, in order to create several continuous weakening zones parallel to each other others, in the direction of the length of the film.

The invention consists, apart from the provisions set forth above, in a number of other provisions to which reference will be made more explicitly to next about a particular embodiment described with reference to the attached drawing, but that is not in absolute limitation

Figure 1 of the drawing is a view in schematic perspective of a package of objects according to the invention.

Figure 2, finally, is a view from above, on a larger scale, of a part of the Figure package one.

Referring to Figure 1 of the drawing, you can see a package 1 of objects 2 made up of cans of preserves, drums or the like, packed with a film 3 of plastic material, generally transparent. Several objects are arranged side by side, on two horizontal floors superimposed on the example depicted in Figure 1. A Separator 4, especially cardboard, separates the two floors.

Movie 3 has been dubbed following a winding direction E to form a wrap around the package consisting of objects 2. The edges of this envelope perpendicular to direction E are welded to each other.

Generally, the arrangement of objects forms  globally a rectangular parallelepiped whose major sides are perpendicular to the winding direction of the film. The open ends of the wrap around the packaging correspond to the smaller faces of the parallelepiped.

The film 3 is subjected to a treatment thermal that causes its narrowing around objects 2 of so that the open ends of the envelope narrow also to form oval openings 5, or lunulas, noticeably in the center of each minor end face of the parallelepiped.

Film 3 presents a preferred address starting D parallel to the major sides of the parallelepiped.

The film 3 is advantageously constituted by a film that comprises at least two layers. The movie is formed by at least two thermoplastic resins, and the direction Preferred tear-off of the film is substantially perpendicular to the extrusion direction E which is the same as the winding direction The film is in particular formed by at least one layer of polyolefin and at least one layer of a ionic copolymer. The movie is, for example, a movie of ionomeric coextruded polyethylene. A film according to the document EP-A-0537080 suits particularly.

The package 1 comprises opening means constituted by a continuous zone A of weakening of the transversely oriented film 3, preferably perpendicularly, to the preferred starting direction D of the movie. Zone A forms a belt 6 that surrounds the package by four faces of the parallelepiped.

In the example depicted in Figure 1, a Only belt 6 is provided, in the middle of the length of the major faces of the parallelepiped, that is half the width of the film 3. It is possible, according to the needs, to provide several 6 parallel belts, spaced following the width of the film 3.

The continuous weakening zone A is thus oriented in the direction of unwinding of the coil of the movie 3.

Zone A comprises a center line 7 of 8 perforations, regularly spaced, orthogonally aligned to address D.

Two outer lines 9, 10 of perforations they are located on both sides of the central line 7 in parallel to this, at the same distance, and include perforations 11a, 11b. The distance h between the perforation lines is comprised preferably between 5 and 30 mm. The width L of the area of weakening is preferably between 30 and 100 mm. This width L corresponds to the distance between the outer edges of the perforations of lines 9 and 10.

The distance f between two perforations 11a or 11b of the outer lines 9 and 10 is greater than the distance g of two successive perforations 8 of the center line 7. In particular, the distance f is double the distance g (f = 2 g).

The perforations 11a, 11b of the two lines exteriors are aligned with a perforation 8 of the line central 7 following an orthogonal direction to this line central.

With f = 2 g, one opening 8 out of two is not surrounded by openings 11a, 11b, as can be seen in Figure 2. The drawings created by these perforations have the shape of a l, stretched horizontally in Fig. 2.

The given example of three parallel lines of perforations, with a central line in which the number of Perforations per unit length is double, it is not limiting. I know could provide on each side of the center line two, or more, lines outer holes more spaced.

The perforations 8, 11a, 11b may be made during extrusion of film 3, or during its rewind, either during printing, or on the device (tying) to make the package.

The perforations are made preferably by means of a device (not shown) consisting of hot or cold needle rollers, with a Reverse part in the form of a cylindrical brush on which the movie. The piercing needles have a diameter of around of 1 mm and a length of about 10 mm and are mounted on some trees in rotation, sliding the film to drill between the needle roller and its reverse side.

The previous cut constituted by zone A is done like this continuously.

In Figure 2 the circular contours 12 of canned cans of the same diameter, tangent to each other, and that define each other spaces voids 13 in the form of four-pointed stars; the centers of the contours 12 are located at the vertices of squares that they have a side length equal to the diameter of the contours. Preferably, zone A covers a succession of empty spaces 13, and the center line 7 of perforations passes substantially in middle of these empty spaces.

The arrangement of the objects in the package and distribution of the zone or zones A over the width of the film so that zone or zones A cover a succession of empty spaces 13. Thus, in the case where zone A is provided at half the width of the movie, the number of objects in a orthogonal row to address E is an even number.

The opening of the film 3 to remove one or Several cans of canning is done as follows.

Pressure is exerted with one finger in one place chosen from zone A, for example in the area where a vacuum 13 formed between the tangent cans with each other and tied, to create an area to grab a tongue J (Fig. 2) whose width corresponds substantially to twice the distance f between two perforations 11a or 11b of the outer lines. The edge of the tab that corresponds to the center line 7 will be trimmed. Just take this edge and pull the tongue J on the direction of the arrow T1 or T2, that is following the direction D preferential starting, perpendicular to the lines of perforations 7, 9, 10 for opening by trimming, in film 3, of a strip K whose width corresponds to that of the tongue J. The tension in tongue J is exerted therefore following a transverse direction, advantageously perpendicular, to the direction of the weakening zone A that forms a belt, and not following the direction of this zone A concretized by the perforation lines 7, 9, 10.

The strip K has a substantially double width of the interval f between two perforations 11a or 11b and, in the practical, between 10 and 60 mm.

The heat shrink film 3 is subjected to thermal stresses during retraction or shrinkage. The distance between perforations 8, 11a, 11b as well as its diameter are chosen based on the mechanical characteristics of the film 3, in order to avoid the formation of holes in the film that would come together under the effect of thermal stresses, while allowing a weakening of the area considered A that allow you to create areas where grab the opening tabs J.

An impression can be made in the area of  weakening A, particularly in perforation lines with in order to materialize them and make them more visible. This impression will give directions on the movements to be made to start and propagate the tearing of the film 3 from the perforations 8, 11a and 11b.

The solution of the invention is of a great ease of implementation allowing clipping adaptation prior at any stage of the production / transformation / use of the product. This solution is complementary to the properties of a movie 3 with good transversal tearing.

The invention guarantees an embodiment in Continuous weakening zone A while preserving the integrity of the heat shrink with respect to a discontinuous procedure with `` die '' type mark.

Claims (14)

1. Package of objects, such as canned cans, drums, bottles, etc., packed with a plastic film (3) that has a preferred direction of removal (D), with several objects (2) arranged next to each other of another on one or several overlapping floors, the film being folded following a winding direction around the objects it encloses, with opening means provided in the film to facilitate its tearing, characterized in that the opening means of the film (3 ) of plastic material comprise a continuous weakening zone (A) oriented transversely to the preferred starting direction (D), and forming a belt (6) surrounding the package, this weakening zone (A) having a mechanical resistance strong enough to withstand the tensile stress exerted on the film to enclose the objects, but low enough to allow u When opening the film without a tool at any point in the area, by creating an area where to grip a tongue and pull on the tongue following a direction transverse to the direction of the weakening zone. 2. Package of objects according to claim 1, characterized in that the continuous weakening zone (A) is perpendicular to the preferred starting direction (D). 3. Package of objects according to claim 1 or 2, characterized in that the continuous weakening zone (A) comprises at least one line (7) of perforations (8). 4. Package of objects according to one of the preceding claims, characterized in that the continuous weakening zone (A) comprises a central line (7) of perforations surrounded by two parallel lines (9, 10) of perforations, separated from the central line, and in which the distance (f) between two successive perforations is greater than the distance (g) between two successive perforations (8) of the center line. 5. Package of objects according to claim 4, characterized in that the distance (f) between two successive perforations (11a, 11b) of the outer lines (9, 10) is equal to twice the distance (g) between two perforations of the center line. 6. Package of objects according to claim 5, characterized in that the perforations (11a, 11b) of the two outer lines (9, 10) are aligned with a perforation (8) of the central line following an orthogonal direction to the central line. 7. Package of objects according to one of the preceding claims, characterized in that the plastic packaging film (3) is a double layer film whose preferred starting direction (D) is perpendicular to the extrusion direction (E). 8. An object package according to claim 7, characterized in that the film (3) is an ionomeric coextruded polyethylene film, in particular constituted by at least one layer of polyolefin and at least one layer of an ionic copolymer. 9. Package of objects according to one of claims 4 to 6, characterized in that the perforation lines are 5 to 30 mm distant, over a width of 30 to 100 mm. 10. Package of objects according to one of the preceding claims, characterized in that the weakening zone (A) of the film covers a succession of empty spaces (13) between the objects (2). 11. Package of objects according to one of the preceding claims, characterized in that the weakening zone (A) of the film is provided at half the width of the film (3). 12. Plastic film for fastening objects of a package according to one of the preceding claims, which has a preferred direction of removal (D), characterized in that it has a continuous weakening zone (A) oriented transversely, in particular perpendicularly, to the preferred starting direction (D), allowing the starting by creating an area where to grip a tongue and traction on the tongue following a direction transverse to the direction of the weakening zone. 13. Plastic film according to claim 12, characterized in that the continuous weakening zone (A) comprises at least one line (7) of regularly spaced perforations, and in particular three perforation lines (7, 9, 10), this is a central line (7) in which the perforations (8) are less separated than in two outer lines (9, 10) parallel to the central line and located on both sides. 14. Method of preparing a plastic film according to claim 13, characterized in that the perforations (8, 11a, 11b) are made during the unwinding or winding of the film (3) before packaging, following its full length, in particular during extrusion, rewinding, printing or tying.